How to grow mahonias

Mahonias are evergreen shrubs that typically thrive in shade. Their winter blooms provide an invaluable source of pollen and nectar for winter-active bees and other pollinators, when there's little else in flower. These are followed by small blueish fruits, which attract birds. With their evergreen spiny foliage, mahonias look fantastic underplanted with contrasting foliage plants that also thrive in shade, for example, elephant ears (Bergenia), fringe cups (Tellima grandiflora) and epimediums.

Mahonia plants are toxic. Mahonia berries and seeds can also be toxic, especially unripe berries. They should not be eaten, particularly by pregnant women, as they can cause uterine contractions.

Where to grow mahonia

The best place to plant mahonia is in moist but well-drained soil in partial or full shade. They can be grown in full sun provided the soil remains moist. Mahonias are ideal for planting under deciduous trees or in a shady mixed border. They’re also a valuable winter plant for wildlife gardens.

Smaller varieties, such as Mahonia eurybracteata subsp. ganpinensis ‘Soft Caress’, can be grown in large containers, though they may eventually need to be planted out in the garden. Mahonias (especially larger varieties) grow best in sheltered locations where cold winds won’t scorch the foliage.

When to plant mahonia

The best time to plant mahonia is in spring or autumn when the soil is moist and the weather is mild, but not too warm. Avoid planting mahonia when the ground is waterlogged or frozen.

How to plant mahonia

Dig a generous hole, adding well-rotted compost and a sprinkling of mycorrhizal fungi. Plant the mahonia, making sure the rootball sits just below the surface of the soil, and firm in well. Water thoroughly.

When planting mahonia in containers, use a loam-based compost, such as peat-free John Innes No.3. Place the container in a sheltered spot in full or partial shade.

How to care for mahonia

Mahonias shouldn’t need watering once they are well established, provided the ground remains moist. Water established plants only if the soil dries out in prolonged hot periods. Apply a mulch of well-rotted garden compost or manure around the base of the plant in spring and autumn, leaving a space around the stem, to help conserve moisture. Plants in the ground shouldn’t need regular feeding. But if plants look like they’re struggling, add a balanced fertiliser in spring. Water plants in containers regularly. Feed with a slow-release fertiliser and apply a balanced liquid feed during the growing season.

Mahonias are hardy and almost all varieties should tolerate winter temperatures in the UK. In very cold winters, plants in containers would benefit from wrapping the pot with hessian or fleece to protect both the roots and the container.

How to prune mahonia

Prune ground-cover mahonias every other year in spring after flowering to encourage bushy growth and remove unwanted suckers. Taller mahonias require little pruning, but should have unwanted suckers removed. Mahonias can be renovation pruned if necessary by cutting back old stems (no more than half of the plant) to strong growth low down. They may take a while to regrow, but should develop healthy, thicker growth in time. Prune the rest of the stems back by a third.

How to propagate mahonia

Mahonia can be successfully propagated by layering or stem cuttings in June and July.

Here, Carol Klein shows you how to take stem cuttings from an evergreen mahonia, using a special technique to cope with its large leaves:

Pests and diseases

Mahonia is generally pest-free, but look out for rusts and powdery mildew in dry weather.

Mahonia varieties to grow

Mahonia x media ‘Winter Sun’ has typical bright yellow, fragrant flowers from late autumn to late winter. It looks particularly good at the back of a shady border. Height x Spread: 4m x 4m

• Buy Mahonia x media 'Winter Sun' from Crocus

Mahonia aquifolium is also known as the Oregon grape, indicating its North American origins. 'Apollo' is a compact cultivar that grows in a neat, spreading dome. The glossy, dark green leaves flush purple in winter with the characteristic yellow flowers appearing in early spring, followed by blue-black berries. H x S: 1m x 1.5m

• Buy Mahonia aquifolium 'Apollo' from Dobies

Mahonia repens is a creeping variety with a low-growing habit, and makes great groundcover in shady areas. The attractive foliage turns purplish in winter and bright yellow, fragrant flowers appear in spring. H x S: 0.5m x 1m

• Buy Mahonia repens from the Agroforestry Trust

Mahonia x media ‘Charity’ has an upright habit and long leaves. Stalks of bright yellow, fragrant flowers are produced at the ends of branches from late autumn to late winter. Mahonia ‘Charity’ is ideal for a shady spot at the back of a border. H x S: 4m x 4m

• Buy Mahonia x media 'Charity' from Suttons

Mahonia eurybracteata subsp. ganpinensis 'Soft Caress' is a variety with finely divided soft evergreen, bamboo-like foliage. Mahonia ‘Soft Caress’ looks completely different to other mahonias and the yellow flowers appear in late summer and autumn. H x S: 1m x 1m

• Buy Mahonia eurybracteata subsp. ganpinensis 'Soft Caress' from Crocus

Mahonia japonica bears lemon-yellow flowers from late autumn to early spring with a sweet lily-of-the-valley fragrance. Suitable for a variety of planting positions, including slopes and banks. H x S: 1.5m x 2.5

• Buy Mahonia japonica from Thompson & Morgan

Find out more about different mahonia varieties in this video clip with Carol Klein, from BBC Gardeners' World:

Frequently asked questions

How tall do mahonias grow?

Mahonias vary greatly in height depending on the variety. Some, like Mahonia ‘Charity’, can reach 5m, whereas lower growing varieties, such as Mahonia repens, might only reach 30cm.

Does mahonia spread?

Some mahonia varieties spread along the ground, producing suckers around the base. But they can be kept in check by pruning and digging out unwanted suckers. Some types of mahonia are considered invasive species in the United States, but the varieties grown in the UK are not considered invasive here.